Control information for multi-user transmissions in WLAN systems

ABSTRACT

In wireless communications for multi-users, an access point may generate a first frame for allocating resources to a plurality of stations. The first frame may contain an indication as to whether a station(s) is allocated at least one of a set of resource units (RUs) of a plurality of RUs, such as a center 26-tone RU. The set of resource units may be based on a channel bandwidth of the wireless communications. The indication may be contained in a common block field of signal fields, such as a common block field of high efficiency (HE) signal content channel(s) of an HE signal field. The station(s) may receive the first frame and determine whether the one of the set of RUs is allocated. The station(s) may transmit a second frame to the access point based on resource allocation information in the first frame. Other methods, apparatus, and computer-readable media are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 16/449,245,filed on Jun. 21, 2019, which is a continuation of application Ser. No.15/231,638, filed on Aug. 8, 2016, now U.S. Pat. No. 10,348,471, whichclaims the benefit of U.S. Provisional Application No. 62/202,756, filedon Aug. 7, 2015; U.S. Provisional Application No. 62/202,758, filed onAug. 7, 2015; U.S. Provisional Application No. 62/234,567, filed on Sep.29, 2015; and U.S. Provisional Application No. 62/347,021, filed on Jun.7, 2016, the entirety of each of which is incorporated herein byreference.

TECHNICAL FIELD

The present description relates in general to wireless communicationsystems and methods, and more particularly to, for example, withoutlimitation, control information for multi-user transmissions in wirelesslocal area network (WLAN) systems.

BACKGROUND

Wireless local area network (WLAN) devices are deployed in diverseenvironments. These environments are generally characterized by theexistence of access points and non-access point stations. Increasedinterference from neighboring devices gives rise to performancedegradation. Additionally, WLAN devices are increasingly required tosupport a variety of applications such as video, cloud access, andoffloading. In particular, video traffic is expected to be the dominanttype of traffic in many high efficiency WLAN deployments. With thereal-time requirements of some of these applications, WLAN users demandimproved performance in delivering their applications, includingimproved power consumption for battery-operated devices.

The description provided in the background section should not be assumedto be prior art merely because it is mentioned in or associated with thebackground section. The background section may include information thatdescribes one or more aspects of the subject technology.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic diagram of an example of a wirelesscommunication network.

FIG. 2 illustrates a schematic diagram of an example of a wirelesscommunication device.

FIG. 3A illustrates a schematic block diagram of an example of atransmitting signal processor in a wireless communication device.

FIG. 3B illustrates a schematic block diagram of an example of areceiving signal processor in a wireless communication device.

FIG. 4 illustrates an example of a timing diagram of interframe space(IFS) relationships.

FIG. 5 illustrates an example of a timing diagram of a carrier sensemultiple access/collision avoidance (CSMA/CA) based frame transmissionprocedure for avoiding collision between frames in a channel.

FIG. 6 illustrates an example of a high efficiency (HE) frame.

FIG. 7 illustrates examples of transmission signal formats that may beavailable for signal transmission.

FIGS. 8A, 8B, and 8C illustrate an example numerology for a 20 MHzchannel bandwidth, a 40 MHz channel bandwidth, and an 80 MHz channelbandwidth, respectively.

FIG. 9 illustrates an example of a high efficiency signal-B field(HE-SIG-B) field.

FIG. 10 illustrates examples of a coding structure of an HE-SIG-B fieldfor 40 MHz, 80 MHz, and 160 MHz channel bandwidth.

FIGS. 11A, 11B, 11C, and 11D illustrate examples of an HE-SIG-B mappingfor a 20 MHz, 40 MHz, an 80 MHz, and a 160 MHz bandwidth, respectively.

FIGS. 12 and 13 illustrate examples of an HE-SIG-B field.

FIG. 14 illustrates an example of an 80 MHz numerology.

FIG. 15 illustrates an example of a coding structure for an HE-SIG-Bfield for a 40 MHz, 80 MHz, and 160 MHz channel bandwidth.

FIGS. 16 and 17 illustrate examples of an HE-SIG-B field including asubfield associated with a special 26 resource unit.

FIG. 18 illustrates an example of an HE-SIG-B field encoded as binaryconvolutional code (BCC) blocks.

FIGS. 19A and 19B illustrate examples of an HE-SIG-B field.

FIG. 20 illustrates an example of an HE-SIG-B field in which the special26 resource unit may be mapped to a different orthogonal frequencydivision multiplexing (OFDM) symbol.

FIG. 21 illustrates an example of an HE-SIG-B field in which the special26 resource unit is mapped to a different OFDM symbol.

FIG. 22 illustrates an example of an HE-SIG-B field in which the special26 resource unit is mapped to a compressed OFDM symbol.

FIG. 23 illustrates an example in which two identical 26-tone resourceunits are paired.

FIG. 24 illustrates an example in which two identical 52-tone resourceunits are paired.

FIG. 25A illustrates an example in a non-continuous RU that includes twoduplicated half-tone resource units may be assigned for a station inorthogonal frequency division multiple access (OFDMA).

FIG. 25B illustrates an example in a non-continuous RU that includes twoduplicated resource units may be assigned for a station in OFDMA.

FIG. 26 illustrates an example of a transmitted physical layerconvergence procedure (PLCP) protocol data unit (PPDU) signal structure.

FIG. 27 illustrates an example of a frequency domain representation of adata field portion of a PPDU for the example of repeated 106 resourceunit transmission in 20 MHz PPDU.

FIGS. 28, 29, and 30 illustrate examples of a frequency domainrepresentation of a data field portion of a PPDU for the example ofrepeated 52 resource unit transmission in 20 MHz PPDU.

FIG. 31 illustrates an example of a symmetric mapping of signals.

FIGS. 32A, 32B, and 32C illustrate flow charts of examples of methodsfor facilitating wireless communication for uplink transmission.

In one or more implementations, not all of the depicted components ineach figure may be required, and one or more implementations may includeadditional components not shown in a figure. Variations in thearrangement and type of the components may be made without departingfrom the scope of the subject disclosure. Additional components,different components, or fewer components may be utilized within thescope of the subject disclosure.

DETAILED DESCRIPTION

The detailed description set forth below is intended as a description ofvarious implementations and is not intended to represent the onlyimplementations in which the subject technology may be practiced. Asthose skilled in the art would realize, the described implementationsmay be modified in various different ways, all without departing fromthe scope of the present disclosure. Accordingly, the drawings anddescription are to be regarded as illustrative in nature and notrestrictive.

The Institute of Electrical and Electronics Engineers (IEEE) 802.11,Task Group ax, provides a new generation of wireless local area network(WLAN). In an aspect, IEEE 802.11ax may be referred to as highefficiency (HE) WLAN (HEW) or simply HE. In one or more implementations,the subject technology may be utilized in IEEE systems, such asHEW-based systems. Several technologies and structures are provided inthe IEEE 802.11ax to facilitate wireless communication. In an aspect,such technologies and/or structures may allow support of reasonableoutdoor performance.

The IEEE 802.11ax introduces the use of orthogonal frequency divisionmultiple access (OFDMA) in WLAN. In an aspect, OFDMA can improve thephysical layer (PHY) efficiency in cases with user frequencymultiplexing gain. In OFDMA, resource units (RUs) form building blocksthat may be assigned to stations (STAs) for communication with an accesspoint (AP). In an aspect, the AP includes a scheduler that can assignone or more resource units to each station participating in theOFDMA-based communication. An amount of control information (e.g.,provided by the AP to STA, and/or vice versa) may be different dependingon the types of technologies/structures applicable to the resource unitsassigned for each STA. In one or more implementations, the subjecttechnology provides an HE signal B (e.g., HE-SIG-B) encoding structure.In an aspect, HE-SIG-B may be referred to as HE-SIG-B field, SIG-B,SIG-B field, or variant thereof. In an aspect, a station may be referredto as a user.

In an aspect, a subfield may be utilized to indicate a type of stationspecific information in a type subfield. The subfield may provideinformation that may be utilized to help determine the size (e.g.,number of symbols) of each STA specific information for assigned STAsand an entire length of HE-SIG-B field. In an aspect, the type subfieldmay help support different combination of subfields depending on STAtype (e.g., single-user (SU) type, multi-user (MU) type, etc.).

In some cases, duplicated orthogonal frequency division multiplexing(OFDM) symbol in the time domain may be utilized to extend a range of alegacy signal (L-SIG) in an HE preamble. In one or more aspects, inorder to extend the range of a data portion (e.g., high efficiencydata), RU repetition in the frequency domain may be helpful for the samepurpose as extending the range of the L-SIG. For instance, withoutpayload available for outdoor circumstance, the large range (e.g.,extended range) of the L-SIG (e.g., due to the duplication) in thepreamble may be meaningless.

In an aspect, duplicated resource unit(s) in the frequency domain inOFDMA may be helpful in allowing robust communication for outdoorcircumstances. The duplicated RUs, which may be contiguous ornon-contiguous RUs, may be repeated and assigned for STAs in OFDMA. Forinstance, data information for a STA is mapped to an RU and repeated(e.g., in the frequency domain) in one or more other RUs.

FIG. 1 illustrates a schematic diagram of an example of a wirelesscommunication network 100. In the wireless communication network 100,such as a wireless local area network (WLAN), a basic service set (BSS)includes a plurality of wireless communication devices (e.g., WLANdevices). In one aspect, a BSS refers to a set of STAs that cancommunicate in synchronization, rather than a concept indicating aparticular area. In the example, the wireless communication network 100includes wireless communication devices 111-115, which may be referredto as stations (STAs).

Each of the wireless communication devices 111-115 may include a mediaaccess control (MAC) layer and a physical (PHY) layer according to anIEEE 802.11 standard. In the example, at least one wirelesscommunication device (e.g., device 111) is an access point (AP). An APmay be referred to as an AP STA, an AP device, or a central station. Theother wireless communication devices (e.g., devices 112-115) may benon-AP STAs. Alternatively, all of the wireless communication devices111-115 may be non-AP STAs in an Ad-hoc networking environment.

An AP STA and a non-AP STA may be collectively called STAs. However, forsimplicity of description, in some aspects, only a non-AP STA may bereferred to as a STA. An AP may be, for example, a centralizedcontroller, a base station (BS), a node-B, a base transceiver system(BTS), a site controller, a network adapter, a network interface card(NIC), a router, or the like. A non-AP STA (e.g., a client deviceoperable by a user) may be, for example, a device with wirelesscommunication capability, a terminal, a wireless transmit/receive unit(WTRU), a user equipment (UE), a mobile station (MS), a mobile terminal,a mobile subscriber unit, a laptop, a non-mobile computing device (e.g.,a desktop computer with wireless communication capability) or the like.In one or more aspects, a non-AP STA may act as an AP (e.g., a wirelesshotspot).

In one aspect, an AP is a functional entity for providing access to adistribution system, by way of a wireless medium, for an associated STA.For example, an AP may provide access to the internet for one or moreSTAs that are wirelessly and communicatively connected to the AP. InFIG. 1 , wireless communications between non-AP STAs are made by way ofan AP. However, when a direct link is established between non-AP STAs,the STAs can communicate directly with each other (without using an AP).

In one or more implementations, OFDMA-based 802.11 technologies areutilized, and for the sake of brevity, a STA refers to a non-AP highefficiency (HE) STA, and an AP refers to an HE AP. In one or moreaspects, a STA may act as an AP.

FIG. 2 illustrates a schematic diagram of an example of a wirelesscommunication device. The wireless communication device 200 includes abaseband processor 210, a radio frequency (RF) transceiver 220, anantenna unit 230, a memory 240, an input interface unit 250, an outputinterface unit 260, and a bus 270, or subsets and variations thereof.The wireless communication device 200 can be, or can be a part of, anyof the wireless communication devices 111-115.

In the example, the baseband processor 210 performs baseband signalprocessing, and includes a medium access control (MAC) processor 211 anda PHY processor 215. The memory 240 may store software (such as MACsoftware) including at least some functions of the MAC layer. The memorymay further store an operating system and applications.

In the illustration, the MAC processor 211 includes a MAC softwareprocessing unit 212 and a MAC hardware processing unit 213. The MACsoftware processing unit 212 executes the MAC software to implement somefunctions of the MAC layer, and the MAC hardware processing unit 213 mayimplement remaining functions of the MAC layer as hardware (MAChardware). However, the MAC processor 211 may vary in functionalitydepending on implementation. The PHY processor 215 includes atransmitting (TX) signal processing unit 280 and a receiving (RX) signalprocessing unit 290. The term TX may refer to transmitting, transmit,transmitted, transmitter or the like. The term RX may refer toreceiving, receive, received, receiver or the like.

The PHY processor 215 interfaces to the MAC processor 211 through, amongothers, transmit vector (TXVECTOR) and receive vector (RXVECTOR)parameters. In one or more aspects, the MAC processor 211 generates andprovides TXVECTOR parameters to the PHY processor 215 to supplyper-packet transmit parameters. In one or more aspects, the PHYprocessor 215 generates and provides RXVECTOR parameters to the MACprocessor 211 to inform the MAC processor 211 of the received packetparameters.

In some aspects, the wireless communication device 200 includes aread-only memory (ROM) (not shown) or registers (not shown) that storeinstructions that are needed by one or more of the MAC processor 211,the PHY processor 215 and/or other components of the wirelesscommunication device 200.

In one or more implementations, the wireless communication device 200includes a permanent storage device (not shown) configured as aread-and-write memory device. The permanent storage device may be anon-volatile memory unit that stores instructions even when the wirelesscommunication device 200 is off. The ROM, registers and the permanentstorage device may be part of the baseband processor 210 or be a part ofthe memory 240. Each of the ROM, the permanent storage device, and thememory 240 may be an example of a memory or a computer-readable medium.A memory may be one or more memories.

The memory 240 may be a read-and-write memory, a read-only memory, avolatile memory, a non-volatile memory, or a combination of some or allof the foregoing. The memory 240 may store instructions that one or moreof the MAC processor 211, the PHY processor 215, and/or anothercomponent may need at runtime.

The RF transceiver 220 includes an RF transmitter 221 and an RF receiver222. The input interface unit 250 receives information from a user, andthe output interface unit 260 outputs information to the user. Theantenna unit 230 includes one or more antennas. When multi-inputmulti-output (MIMO) or multi-user MIMO (MU-MIMO) is used, the antennaunit 230 may include more than one antenna.

The bus 270 collectively represents all system, peripheral, and chipsetbuses that communicatively connect the numerous internal components ofthe wireless communication device 200. In one or more implementations,the bus 270 communicatively connects the baseband processor 210 with thememory 240. From the memory 240, the baseband processor 210 may retrieveinstructions to execute and data to process in order to execute theprocesses of the subject disclosure. The baseband processor 210 can be asingle processor, multiple processors, or a multi-core processor indifferent implementations. The baseband processor 210, the memory 240,the input interface unit 250, and the output interface unit 260 maycommunicate with each other via the bus 270.

The bus 270 also connects to the input interface unit 250 and the outputinterface unit 260. The input interface unit 250 enables a user tocommunicate information and select commands to the wirelesscommunication device 200. Input devices that may be used with the inputinterface unit 250 may include any acoustic, speech, visual, touch,tactile and/or sensory input device, e.g., a keyboard, a pointingdevice, a microphone, or a touchscreen. The output interface unit 260may enable, for example, the display or output of videos, images, audio,and data generated by the wireless communication device 200. Outputdevices that may be used with the output interface unit 260 may includeany visual, auditory, tactile, and/or sensory output device, e.g.,printers and display devices or any other device for outputtinginformation. One or more implementations may include devices thatfunction as both input and output devices, such as a touchscreen.

One or more implementations can be realized in part or in whole using acomputer-readable medium. In one aspect, a computer-readable mediumincludes one or more media. In one or more aspects, a computer-readablemedium is a tangible computer-readable medium, a computer-readablestorage medium, a non-transitory computer-readable medium, amachine-readable medium, a memory, or some combination of the foregoing(e.g., a tangible computer-readable storage medium, or a non-transitorymachine-readable storage medium). In one aspect, a computer is amachine. In one aspect, a computer-implemented method is amachine-implemented method.

A computer-readable medium may include storage integrated into aprocessor and/or storage external to a processor. A computer-readablemedium may be a volatile, non-volatile, solid state, optical, magnetic,and/or other suitable storage device, e.g., RAM, ROM, PROM, EPROM, aflash, registers, a hard disk, a removable memory, or a remote storagedevice.

In one aspect, a computer-readable medium comprises instructions storedtherein. In one aspect, a computer-readable medium is encoded withinstructions. In one aspect, instructions are executable by one or moreprocessors (e.g., 210, 211, 212, 213, 215, 280, 290) to perform one ormore operations or a method. Instructions may include, for example,programs, routines, subroutines, data, data structures, objects,sequences, commands, operations, modules, applications, and/orfunctions. Those skilled in the art would recognize how to implement theinstructions.

A processor (e.g., 210, 211, 212, 213, 215, 280, 290) may be coupled toone or more memories (e.g., one or more external memories such as thememory 240, one or more memories internal to the processor, one or moreregisters internal or external to the processor, or one or more remotememories outside of the device 200), for example, via one or more wiredand/or wireless connections. The coupling may be direct or indirect. Inone aspect, a processor includes one or more processors. A processor,including a processing circuitry capable of executing instructions, mayread, write, or access a computer-readable medium. A processor may be,for example, an application specific integrated circuit (ASIC), adigital signal processor (DSP), or a field programmable gate array(FPGA).

In one aspect, a processor (e.g., 210, 211, 212, 213, 215, 280, 290) isconfigured to cause one or more operations of the subject disclosure tooccur. In one aspect, a processor is configured to cause an apparatus(e.g., a wireless communication device 200) to perform operations or amethod of the subject disclosure. In one or more implementations, aprocessor configuration involves having a processor coupled to one ormore memories. A memory may be internal or external to the processor.Instructions may be in a form of software, hardware or a combinationthereof. Software instructions (including data) may be stored in amemory. Hardware instructions may be part of the hardware circuitrycomponents of a processor. When the instructions are executed orprocessed by one or more processors, (e.g., 210, 211, 212, 213, 215,280, 290), the one or more processors cause one or more operations ofthe subject disclosure to occur or cause an apparatus (e.g., a wirelesscommunication device 200) to perform operations or a method of thesubject disclosure.

FIG. 3A illustrates a schematic block diagram of an example of atransmitting signal processing unit 280 in a wireless communicationdevice. The transmitting signal processing unit 280 of the PHY processor215 includes an encoder 281, an interleaver 282, a mapper 283, aninverse Fourier transformer (IFT) 284, and a guard interval (GI)inserter 285.

The encoder 281 encodes input data. For example, the encoder 281 may bea forward error correction (FEC) encoder. The FEC encoder may include abinary convolutional code (BCC) encoder followed by a puncturing device,or may include a low-density parity-check (LDPC) encoder. Theinterleaver 282 interleaves the bits of each stream output from theencoder 281 to change the order of bits. In one aspect, interleaving maybe applied only when BCC encoding is employed. The mapper 283 maps thesequence of bits output from the interleaver 282 into constellationpoints.

When MIMO or MU-MIMO is employed, the transmitting signal processingunit 280 may use multiple instances of the interleaver 282 and multipleinstances of the mapper 283 corresponding to the number of spatialstreams (N_(SS)). In the example, the transmitting signal processingunit 280 may further include a stream parser for dividing outputs of theBCC encoders or the LDPC encoder into blocks that are sent to differentinterleavers 282 or mappers 283. The transmitting signal processing unit280 may further include a space-time block code (STBC) encoder forspreading the constellation points from the number of spatial streamsinto a number of space-time streams (N_(STS)) and a spatial mapper formapping the space-time streams to transmit chains. The spatial mappermay use direct mapping, spatial expansion, or beamforming depending onimplementation. When MU-MIMO is employed, one or more of the blocksbefore reaching the spatial mapper may be provided for each user.

The IFT 284 converts a block of the constellation points output from themapper 283 or the spatial mapper into a time domain block (e.g., asymbol) by using an inverse discrete Fourier transform (IDFT) or aninverse fast Fourier transform (IFFT). If the STBC encoder and thespatial mapper are employed, the IFT 284 may be provided for eachtransmit chain.

When MIMO or MU-MIMO is employed, the transmitting signal processingunit 280 may insert cyclic shift diversities (CSDs) to preventunintentional beamforming. The CSD insertion may occur before or afterthe inverse Fourier transform operation. The CSD may be specified pertransmit chain or may be specified per space-time stream. Alternatively,the CSD may be applied as a part of the spatial mapper.

The GI inserter 285 prepends a GI to the symbol. The transmitting signalprocessing unit 280 may optionally perform windowing to smooth edges ofeach symbol after inserting the GI. The RF transmitter 221 converts thesymbols into an RF signal and transmits the RF signal via the antennaunit 230. When MIMO or MU-MIMO is employed, the GI inserter 285 and theRF transmitter 221 may be provided for each transmit chain.

FIG. 3B illustrates a schematic block diagram of an example of areceiving signal processing unit 290 in a wireless communication device.The receiving signal processing unit 290 of the PHY processor 215includes a GI remover 291, a Fourier transformer (FT) 292, a demapper293, a deinterleaver 294, and a decoder 295.

The RF receiver 222 receives an RF signal via the antenna unit 230 andconverts the RF signal into one or more symbols. In some aspects, the GIremover 291 removes the GI from the symbol. When MIMO or MU-MIMO isemployed, the RF receiver 222 and the GI remover 291 may be provided foreach receive chain.

The FT 292 converts the symbol (e.g., the time domain block) into ablock of the constellation points by using a discrete Fourier transform(DFT) or a fast Fourier transform (FFT) depending on implementation. Inone or more implementations, the FT 292 is provided for each receivechain.

When MIMO or MU-MIMO is employed, the receiving signal processing unit290 may further include a spatial demapper for converting the Fouriertransformed receiver chains to constellation points of the space-timestreams, and a STBC decoder (not shown) for despreading theconstellation points from the space-time streams into the spatialstreams.

The demapper 293 demaps the constellation points output from the FT 292or the STBC decoder to the bit streams. If the LDPC encoding is used,the demapper 293 may further perform LDPC tone demapping before theconstellation demapping. The deinterleaver 294 deinterleaves the bits ofeach stream output from the demapper 293. In one or moreimplementations, deinterleaving may be applied only when BCC decoding isused.

When MIMO or MU-MIMO is employed, the receiving signal processing unit290 may use multiple instances on the demapper 293 and multipleinstances of the deinterleaver 294 corresponding to the number ofspatial streams. In the example, the receiving signal processing unit290 may further include a stream deparser for combining the streamsoutput from the deinterleavers 294.

The decoder 295 decodes the streams output from the deinterleaver 294and/or the stream deparser. For example, the decoder 295 may be an FECdecoder. The FEC decoder may include a BCC decoder or an LDPC decoder.

FIG. 4 illustrates an example of a timing diagram of interframe space(IFS) relationships. In this example, a data frame, a control frame, ora management frame can be exchanged between the wireless communicationdevices 111-115 and/or other WLAN devices.

Referring to the timing diagram 400, during the time interval 402,access is deferred while the medium (e.g., a wireless communicationchannel) is busy until a type of IFS duration has elapsed. At timeinterval 404, immediate access is granted when the medium is idle for aduration that is equal to or greater than a distributed coordinationfunction IFS (DIFS) 410 duration or arbitration IFS (AIFS) 414 duration.In turn, a next frame 406 may be transmitted after a type of IFSduration and a contention window 418 have passed. During the time 408,if a DIFS has elapsed since the medium has been idle, a designated slottime 420 is selected and one or more backoff slots 422 are decrementedas long as the medium is idle.

The data frame is used for transmission of data forwarded to a higherlayer. In one or more implementations, a WLAN device transmits the dataframe after performing backoff if DIFS 410 has elapsed from a time whenthe medium has been idle.

The management frame is used for exchanging management information thatis not forwarded to the higher layer. Subtype frames of the managementframe include a beacon frame, an association request/response frame, aprobe request/response frame, and an authentication request/responseframe.

The control frame is used for controlling access to the medium. Subtypeframes of the control frame include a request to send (RTS) frame, aclear to send (CTS) frame, and an ACK frame. In the case that thecontrol frame is not a response frame of the other frame (e.g., aprevious frame), the WLAN device transmits the control frame afterperforming backoff if the DIFS 410 has elapsed. In the case that thecontrol frame is the response frame of the other frame, the WLAN devicetransmits the control frame without performing backoff if a short IFS(SIFS) 412 has elapsed. For example, the SIFS may be 16 microseconds.The type and subtype of frame may be identified by a type field and asubtype field in a frame control field of the frame.

On the other hand, a Quality of Service (QoS) STA may transmit the frameafter performing backoff if AIFS 414 for access category (AC), e.g.,AIFS[AC], has elapsed. In this case, the data frame, the managementframe, or the control frame that is not the response frame may use theAIFS[AC].

In one or more implementations, a point coordination function (PCF)enabled AP STA transmits the frame after performing backoff if a PCF IFS(PIFS) 416 has elapsed. In this example, the PIFS 416 duration is lessthan the DIFS 410 but greater than the SIFS 412. In some aspects, thePIFS 416 is determined by incrementing the SIFS 412 duration by adesignated slot time 420.

FIG. 5 illustrates an example of a timing diagram of a carrier sensemultiple access/collision avoidance (CSMA/CA) based frame transmissionprocedure for avoiding collision between frames in a channel. In FIG. 5, any one of the wireless communication devices 111-115 in FIG. 1 can bedesignated as one of STA1, STA2 or STA3. In this example, the wirelesscommunication device 111 is designated as STA1, the wirelesscommunication device 112 is designated as STA2, and the wirelesscommunication device 113 is designated as STA3. While the timing of thewireless communication devices 114 and 115 is not shown in FIG. 5 , thetiming of the devices 114 and 115 may be the same as that of STA2.

In this example, STA1 is a transmit WLAN device for transmitting data,STA2 is a receive WLAN device for receiving the data, and STA3 is a WLANdevice that may be located at an area where a frame transmitted from theSTA1 and/or a frame transmitted from the STA2 can be received by theSTA3.

The STA1 may determine whether the channel (or medium) is busy bycarrier sensing. The STA1 may determine the channel occupation based onan energy level on the channel or correlation of signals in the channel.In one or more implementations, the STA1 determines the channeloccupation by using a network allocation vector (NAV) timer.

When determining that the channel is not used by other devices duringthe DIFS 410 (e.g., the channel is idle), the STA1 may transmit an RTSframe 502 to the STA2 after performing backoff Upon receiving the RTSframe 502, the STA2 may transmit a CTS frame 506 as a response of theCTS frame 506 after the SIFS 412.

When the STA3 receives the RTS frame 502, the STA3 may set a NAV timerfor a transmission duration representing the propagation delay ofsubsequently transmitted frames by using duration information involvedwith the transmission of the RTS frame 502 (e.g., NAV(RTS) 510). Forexample, the STA3 may set the transmission duration expressed as thesummation of a first instance of the SIFS 412, the CTS frame 506duration, a second instance of the SIFS 412, a data frame 504 duration,a third instance of the SIFS 412 and an ACK frame 508 duration.

Upon receiving a new frame (not shown) before the NAV timer expires, theSTA3 may update the NAV timer by using duration information included inthe new frame. The STA3 does not attempt to access the channel until theNAV timer expires.

When the STA1 receives the CTS frame 506 from the STA2, the STA1 maytransmit the data frame 504 to the STA2 after the SIFS 412 elapses froma time when the CTS frame 506 has been completely received. Uponsuccessfully receiving the data frame 504, the STA2 may transmit the ACKframe 508 after the SIFS 412 elapses as an acknowledgment of receivingthe data frame 504.

When the NAV timer expires, the STA3 may determine whether the channelis busy by the carrier sensing. Upon determining that the channel is notused by the other WLAN devices (e.g., STA1, STA2) during the DIFS 410after the NAV timer has expired, the STA3 may attempt the channel accessafter a contention window 418 has elapsed. In this example, thecontention window 418 may be based on a random backoff.

FIG. 6 illustrates an example of a high efficiency (HE) frame 600. TheHE frame 600 is a physical layer convergence procedure (PLCP) protocoldata unit (or PPDU) format. An HE frame may be referred to as an OFDMAframe, a PPDU, a PPDU format, an OFDMA PPDU, an MU PPDU, another similarterm, or vice versa. An HE frame may be simply referred to as a framefor convenience. A transmitting station (e.g., AP, non-AP station) maygenerate the HE frame 600 and transmit the HE frame 600 to a receivingstation. The receiving station may receive, detect, and process the HEframe 600. The HE frame 600 may include an L-STF field, an L-LTF field,an L-SIG field, an RL-SIG field, an HE-SIG-A field, an HE-SIG-B field,an HE-STF field, an HE-LTF field, and an HE-DATA field. The HE-SIG-Afield may include N_(HESIGA) symbols, the HE-SIG-B field may includeN_(HESIGB) symbols, the HE-LTF field may include N_(HELTF) symbols, andthe HE-DATA field may include N_(DATA) symbols. In an aspect, theHE-DATA field may also be referred to as a payload field, data, datasignal, data portion, payload, PSDU, or Media Access Control (MAC)Protocol Data Units (MPDU) (e.g., MAC frame).

In one or more implementations, an AP may transmit frame for downlink(DL) using a frame format shown in this figure or a variation thereof(e.g., without any or some portions of an HE header). A STA may transmita frame for uplink (UL) using a frame format shown in this figure or avariation thereof (e.g., without any or some portions of an HE header).

The table below provides examples of characteristics associated with thevarious components of the HE frame 600.

DFT Subcarrier Element Definition Duration period GI Spacing DescriptionLegacy(L)- Non-high 8 μs — — equivalent L-STF of a STF throughput to1,250 kHz non-trigger- (HT) Short based PPDU Training has a fieldperiodicity of 0.8 μs with 10 periods. L-LTF Non-HT 8 μs 3.2 μs 1.6 μs312.5 kHz Long Training field L-SIG Non-HT 4 μs 3.2 μs 0.8 μs 312.5 kHzSIGNAL field RL-SIG Repeated 4 μs 3.2 μs 0.8 μs 312.5 kHz Non-HT SIGNALfield HE-SIG-A HE N_(HESIGA) * 3.2 μs 0.8 μs 312.5 kHz HE-SIG-A isSIGNAL A 4 μs duplicated on field each 20 MHz segment after the legacypreamble to indicate common control information. N_(HESIGA) means thenumber of OFDM symbols of the HE-SIG-A field and is equal to 2 or 4.HE-SIG-B HE N_(HESIGB) * 3.2 μs 0.8 μs 312.5 kHz N_(HESIGB) SIGNAL B 4μs means the field number of OFDM symbols of the HE-SIG-B field and isvariable. DL MU packet contains HE-SIG-B. Single user (SU) packets andUL Trigger based packets do not contain HE-SIG-B. HE-STF HE Short 4 or 8μs — — non- HE-STF of a Training trigger- non-trigger- field based basedPPDU PPDU: has a (equivalent periodicity of to) 1,250 0.8 μs with 5 kHz;periods. A non- trigger- trigger-based based PPDU is not PPDU: sent in(equivalent response to a to) 625 trigger frame. kHz The HE-STF of atrigger- based PPDU has a periodicity of 1.6 μs with 5 periods. Atrigger-based PPDU is a UL PPDU sent in response to a trigger frame.HE-LTF HE Long N_(HELTF) * 2 × LTF: supports 2 × LTF: HE PPDU Training(DFT 6.4 μs 0.8, 1.6, (equivalent may support field period + 4 × LTF:3.2 μs to) 156.25 2 × LTF mode GI) μs 12.8 μs kHz; and 4 × LTF 4 × LTF:mode. 78.125 kHz In the 2 × LTF mode, HE-LTF symbol excluding GI isequivalent to modulating every other tone in an OFDM symbol of 12.8 μsexcluding GI, and then removing the second half of the OFDM symbol intime domain. N_(HELTF) means the number of HE-LTF symbols and is equalto 1, 2, 4, 6, 8. HE-DATA HE DATA N_(DATA) * 12.8 μs  supports 78.125kHz  N_(DATA) means field (DFT 0.8, 1.6, the number of period + 3.2 μsHE data GI) μs symbols.

Referring to FIG. 6 , the HE frame 600 contains a header and a datafield. The header includes a legacy header comprised of the legacy shorttraining field (L-STF), the legacy long training field (L-LTF), and thelegacy signal (L-SIG) field. These legacy fields contain symbols basedon an early design of an IEEE 802.11 specification. Presence of thesesymbols may facilitate compatibility of new designs with the legacydesigns and products. The legacy header may be referred to as a legacypreamble. In one or more aspects, the term header may be referred to asa preamble.

In one or more implementations, the legacy STF, LTF, and SIG symbols aremodulated/carried with FFT size of 64 on a 20 MHz sub-channel and areduplicated every 20 MHz if the frame has a channel bandwidth wider than20 MHz (e.g., 40 MHz, 80 MHz, 160 MHz). Therefore, the legacy field(i.e., the STF, LTF, and SIG fields) occupies the entire channelbandwidth of the frame. The L-STF field may be utilized for packetdetection, automatic gain control (AGC), and coarse frequency-offset(FO) correction. In one aspect, the L-STF field does not utilizefrequency domain processing (e.g., FFT processing) but rather utilizestime domain processing. The L-LTF field may be utilized for channelestimation, fine frequency-offset correction, and symbol timing. In oneor more aspects, the L-SIG field may contain information indicative of adata rate and a length (e.g., in bytes) associated with the HE frame600, which may be utilized by a receiver of the HE frame 600 tocalculate a time duration of a transmission of the HE frame 600.

The header may also include an HE header comprised of an HE-SIG-A fieldand an HE-SIG-B field. The HE header may be referred to as a non-legacyheader. These fields contain symbols that carry control informationassociated with each PLCP service data unit (PSDU) and/or radiofrequency (RF), PHY, and MAC properties of a PPDU. In one aspect, theHE-SIG-A field can be carried/modulated using an FFT size of 64 on a 20MHz basis. The HE-SIG-B field can be carried/modulated using an FFT sizeof e.g., 64 or 256 on a 20 MHz basis depending on implementation. TheHE-SIG-A and HE-SIG-B fields may occupy the entire channel bandwidth ofthe frame. In some aspects, the size of the HE-SIG-A field and/or theHE-SIG-B field is variable (e.g., can vary from frame to frame). In anaspect, the HE-SIG-B field is not always present in all frames. Tofacilitate decoding of the HE frame 600 by a receiver, the size of(e.g., number of symbols contained in) the HE-SIG-B field may beindicated in the HE-SIG-A field. In some aspects, the HE header alsoincludes the repeated L-SIG (RL-SIG) field, whose content is the same asthe L-SIG field. In an aspect, the HE-SIG-A and HE-SIG-B fields may bereferred as control signal fields. In an aspect, the HE-SIG-A field maybe referred to as a SIG-A field, SIG-A, or SIGA. Similarly, in anaspect, the HE-SIG-B field may be referred to as a SIG-B field, SIG-B,or SIGB.

The HE header may further include HE-STF and HE-LTF fields, whichcontain symbols used to perform necessary RF and PHY processing for eachPSDU and/or for the whole PPDU. The HE-LTF symbols may bemodulated/carried with an FFT size of 256 for 20 MHz bandwidth andmodulated over the entire bandwidth of the frame. Thus, the HE-LTF fieldmay occupy the entire channel bandwidth of the frame. In one aspect, theHE-LTF field may occupy less than the entire channel bandwidth. In oneaspect, the HE-LTF field may be transmitted using a code-frequencyresource. In one aspect, an HE-LTF sequence may be utilized by areceiver to estimate MIMO channel between the transmitter and thereceiver. Channel estimation may be utilized to decode data transmittedand compensate for channel properties (e.g., effects, distortions). Forexample, when a preamble is transmitted through a wireless channel,various distortions may occur, and a training sequence in the HE-LTFfield is useful to reverse the distortion. This may be referred to asequalization. To accomplish this, the amount of channel distortion ismeasured. This may be referred to as channel estimation. In one aspect,channel estimation is performed using an HE-LTF sequence, and thechannel estimation may be applied to other fields that follow the HE-LTFsequence.

The HE-STF symbols may have a fixed pattern and a fixed duration. Forexample, the HE-STF symbols may have a predetermined repeating pattern.In one aspect, the HE-STF symbols do not require FFT processing. The HEframe 600 may include the data field, represented as HE-DATA, thatcontains data symbols. The data field may also be referred to as apayload field, data, payload or PSDU.

In one or more aspects, additional one or more HE-LTF fields may beincluded in the header. For example, an additional HE-LTF field may belocated after a first HE-LTF field. In one or more implementations, a TXsignal processing unit 280 (or an IFT 284) illustrated in FIG. 3A maycarry out the modulation described in this paragraph as well as themodulations described in other paragraphs above. In one or moreimplementations, an RX signal processing unit 290 (or an FT 292) mayperform demodulation for a receiver.

FIG. 7 illustrates four different transmission signal formats that maybe available for signal transmission (e.g., HE-based transmission). Thefour transmission formats include a format for an SU PPDU, an MU PPDU,an extended range PPDU, and a trigger based PPDU. The SU PPDU format canbe used in both downlink (DL) and uplink (UL) to transmit SU-MIMOsignals. The MU PPDU format can be used in downlink to transmit signalsfrom a single AP to one or more STAs. Additionally, the MU PPDU formatcan be used in uplink to transmit a signal from a single STA to an AP.The extended range PPDU format is similar to the SU PPDU format. In anaspect, the extended range PPDU format may be used to convey informationin coverage limited cases. The trigger based PPDU format can be used totransmit a signal from a STA to an AP. In an aspect, the trigger basedPPDU is only sent as a response to a trigger frame (e.g., received by aSTA from an AP) that contains, for each participating STA, informationabout the frequency and spatial resources (e.g., exact frequency andspatial resources) to be used by each participating station to transmitsignals. Multiple STAs can transmit the trigger based PPDU at a giventime. In an aspect, the data signals (e.g., HE-DATA fields) fromdifferent STAs may be orthogonally multiplexed in the frequency and/orspatial domain. In an aspect, the multiple STAs may transmit the triggerbased PPDU at a given time as part of a multi-user (MU) uplink (UL) PPDUtransmission. In an aspect, all of the transmission formats utilizeresource unit(s) as basic building blocks for OFDMA-based transmission.

In one or more implementations, in OFDMA, an access point may allocatedifferent portions of a channel bandwidth to different stations. In oneaspect, a portion of a channel bandwidth is allocated to a station. Inone aspect, a portion of a channel bandwidth may be a resource unit (RU)or a resource allocation block. In another aspect, a portion of achannel bandwidth may be one or more resource units. In yet anotheraspect, a portion of a channel bandwidth may be one or more blocks of achannel bandwidth. Each resource unit includes multiple tones. In anaspect, a size of a resource unit may be the number of tones included inthe resource unit. In an aspect, a resource unit may be referred to as ablock, subband, band, frequency subband, frequency band, or variantthereof (e.g., frequency block). A tone may be referred to assubcarrier. Each tone may be associated with or otherwise identified bya tone index or a subcarrier index. A tone index may be referred to as asubcarrier index.

In one or more aspects, the resource units that may be allocated for achannel bandwidth may be provided by an OFDMA numerology. In an aspect,the OFDMA numerology may be referred to as an OFDMA structure or anumerology. The numerology provides different manners by which toallocate resources for a channel bandwidth (e.g., 20 MHz, 40 MHz, 80MHz, 80+80/160 MHz channel bandwidth) into individual resource units. Inother words, the numerology provides potential resources for OFDMA forstations that support the IEEE 802.11ax specification.

In some aspects, the OFDMA numerology and/or resource unit(s) providedby the numerology are optimized depending on a communication system,such as by taking into consideration tradeoff between OFDMA gain andsignaling overhead. In an aspect, the OFDMA gain may include ascheduling/frequency selectivity gain. The OFDMA gain may be achieved byassigning resources to the stations based on frequency selectivity ofthe stations. For instance, in an aspect, it may be assumed that somespecific set of size and position of RUs are given, and BCC interleaverand/or LDPC tone mapper parameters are optimized for certain RUs for agiven communication system. In an aspect, the RUs are building blocks tobe utilized by a scheduler to assign resources to different stations(e.g., in UL/DL OFDMA). For instance, the scheduler may assign one ormore RUs to a station.

FIGS. 8A, 8B, and 8C illustrate examples of a numerology for a 20 MHzchannel bandwidth, a 40 MHz channel bandwidth, and an 80 MHz channelbandwidth, respectively. In an aspect, transmission associated with a 20MHz, 40 MHz, 80 MHz, and 80+80/160 MHz channel bandwidth may be referredto as 20 MHz, 40 MHz, 80 MHz, and 80+80/160 MHz transmission,respectively. In an aspect, the 20 MHz, 40 MHz, and 80 MHz channelbandwidth may be denoted as HE20, HE40, and HE80, respectively.

In this regard, FIGS. 8A, 8B, and 8C illustrate the resource units forthe 20 MHz, 40 MHz, and 80 MHz channel bandwidth, respectively. Forinstance, as shown in FIG. 8A, the 20 MHz OFDMA structure uses 26-toneRU(s), 52-tone RU(s), and 106-tone RU(s) at fixed positions. As shown inFIG. 8B, the 40 MHz OFDMA structure may be two replicas of the 20 MHzOFDMA structure. As shown in FIG. 8C, the 80 MHz OFDMA structure may beformed of two replicas of the 40 MHz OFDMA structure on top of onecentral 26-tone RU (denoted as 805). Within 80 MHz, the OFDMA designsupports six different RU sizes: 26, 52, 106, 242, 484, and 996. In anaspect, the size of an RU may be the number of tones included in the RU.The 80+80/160 MHz OFDMA structure may be two replicas of the 80 MHzOFDMA structure. Each station (e.g., user) can be allocated one or moreof the RUs shown in FIG. 8A, 8B, or 8C when the channel bandwidth is 20MHz, 40 MHz, or 80 MHz, respectively. It is noted that the bottom-mostrow in each of FIGS. 8A, 8B, and 8C illustrate the non-OFDMA case.

In the 20 MHz and 80 MHz channel bandwidth, the central 26 RU is splitinto two 13 subcarrier (or tone) components due to direct current (DC)subcarriers (or tones). In particular, as shown in FIGS. 8A and 8C, thetwo 13 subcarrier (or tone) components are separated by 7 DC subcarriers(or tones). In an aspect, on top of OFDMA, MU-MIMO may be integrated tothe RUs. Such integration of MU-MIMO to the RUs may outperform SU OFDMAin some cases considering overhead. In an aspect, each of the 80+80 MHztransmission and 160 MHz transmission may have similar OFDMA structures,with a center 26 RU being present at the center of each 80 MHz band and7 DC subcarriers (or tones) between split tones. Hence, the 80+80 MHztransmission has two center 26 RUs, where each center 26 RU is splitinto two 13 subcarriers (or tones), and the two 13 subcarriers (ortones) are separated by 7 DC subcarriers (or tones). Likewise, the 160MHz transmission has two center 26 RUs, where each center 26 RU is splitinto two 13 subcarriers (or tones), and the two 13 subcarriers (ortones) are separated by 7 DC subcarriers (or tones).

FIG. 9 illustrates an example of an HE-SIG-B field. The HE-SIG-B fieldmay include a common subfield followed by one or more user specificsubfields. A last user specific subfield may be followed by padding(e.g., padding bits). The control information transmitted in theHE-SIG-B field may include common control information, contained in thecommon subfield, and station (STA) specific information, contained inthe user specific subfields.

In an aspect, the common subfield may be referred to as a common field,common information field, a common block field, or variants thereof(e.g., common block subfield). In an aspect, the one or more userspecific subfields form a user specific field. In an aspect, userspecific information may be referred to as station (STA) specificinformation. In an aspect, the common control information includescontrol information that needs to be shared for all STAs. In an aspect,the STA specific control information is control information dedicated toa specific STA. For instance, each user specific subfield in FIG. 9 mayinclude control information for one station.

The common subfield may identify designated stations and include theinformation (e.g., resource allocation information) for all thedesignated stations. In an aspect, the common subfield may containinformation regarding the resource unit allocation/assignment such asthe RU arrangement in the frequency domain, the RUs allocated forMU-MIMO and/or OFDMA, and the number of users in MU-MIMO and/or OFDMAallocations. In this regard, the HE-SIG-B field may be a control signalfield that includes resource allocation information (e.g., RU allocationinformation) as well as other control signaling information forfacilitating correct reception of data signals. In an aspect, theresource allocation information as well as other control signalinginformation may be necessary for correct reception of data signals. Thecommon subfield may include a subfield type (e.g., SU or MU) for eachuser specific subfield.

One or more of the user specific subfields are for each designatedreceiving STA. In an aspect, the user specific subfield may be one oftwo types, SU subfield type or MU subfield type. Depending on theresource allocation information, each user specific subfield may be oneof the SU subfield or the MU subfield. In an aspect, a size/length ofthe user specific subfield may be based at least in part on the type ofthe user specific subfield and the number of user specific subfields(e.g., the number of stations). The SU subfield may include a stationidentifier (STA-ID) that addresses the station, number of space timestreams N_(STS), modulation and coding scheme (MCS), beamforming (BF)(e.g., transmit beamforming (TxBF)), coding (e.g., indication for use ofLDPC), etc. The MU subfield may contain information similar to the SUsubfield, including, for example, the STA-ID, N_(STS), MCS, and coding.In an aspect, a distinction between SU and MU subfield is that MUsubfield contains information regarding spatial stream configuration(e.g., in spatial configuration field(s)). In an aspect, the MU subfieldmay contain a total number of space time streams, denoted as L_(STS). Insome cases, the L_(STS) may be utilized for determining the number ofHE-LTF symbols.

In an aspect, in an SU-MIMO transmission mode, each user occupiesN_(STS) space time streams. In an aspect, in an MU-MIMO transmissionmode, each user occupies a subset of the total number of space timestreams. The total number of space time streams may be denoted asL_(STS) and the subset may be denoted as N_(STS). Thus, the N_(STS) of auser k is equal to or smaller than the L_(STS). In an aspect, in theMU-MIMO transmission mode, the transmitter indicates the logical orderof the spatial stream assignment to each user, provided by the M_(STS)and N_(STS) in FIG. 9 . For example, the transmitter can indicate astarting spatial stream index, M_(STS), and the number of space timestreams, N_(STS), for a specific user. In an aspect, as long as thespace time streams for different MU-MIMO users do not overlap, each usercan correctly receive signals from the transmitter. In an aspect, whenthe size of station specific information for both SU and MU (e.g.,SU-MIMO, MU-MIMO) are the same, the type information need not beutilized to calculate the length of the SIG-B field.

In one or more aspects, for channel bandwidths greater than or equal to40 MHz, the number of 20 MHz subbands carrying different content forHE-SIG-B is two. FIG. 10 illustrates examples of a coding structure ofan HE-SIG-B field for 40 MHz, 80 MHz, and 160 MHz channel bandwidth. Inan aspect, the SIG-B coding structure may be referred to as a SIG-Bfield mapping structure. Each square in FIG. 10 represents a 20 MHzsubband, and the number 1 and 2 represent different signaling/controlinformation. In an aspect, the “1” may be referred to as coding block 1or SIG-B coding block 1. Similarly, in an aspect, the “2” may bereferred to as coding block 2 or SIG-B coding block 2. In an aspect, acoding block may be referred to as a content channel, such that codingblock 1 and coding block 2 may be referred to as content channel 1 (orSIG-B content channel 1) and content channel 2 (or SIG-B content channel2), respectively. In an aspect, coding block 1 may be referred to as afirst HE-SIG-B field and coding block 2 may be referred to as a secondHE-SIG-B field. The HE-SIG-B field of FIG. 10 may be composed of one ormore first HE-SIG-B fields in one or more subbands (e.g., 20 MHzsubbands) and one or more second HE-SIG-B fields in the remainingsubband(s).

In some aspects, in 20 MHz transmission, a single SIG-B coding block istransmitted. In some aspects, in 40 MHz transmission, two SIG-B codingblocks, represented as 1 and 2, are transmitted. Each of the two SIG-Bcoding blocks may span one of the two 20 MHz subbands that form the 40MHz channel bandwidth. Each of the two SIG-B coding blocks may conveyinformation about resources in its corresponding 20 MHz bandwidth.

In some aspects, in 80 MHz transmission, two SIG-B coding blocks aretransmitted. Each of the two SIG-B coding blocks may span a respective20 MHz bandwidth. In an aspect, each of the two SIG-B coding blocks isreplicated twice in the frequency domain, resulting in a SIG-B fieldthat spans the 80 MHz channel bandwidth in a coding block 1, codingblock 2, coding block 1, coding block 2 (1-2-1-2) structure. In thisregard, as shown in FIG. 10 for 80 MHz, in an aspect, a first and third20 MHz bandwidth may contain the same content, represented as 1, whereasa second and fourth 20 MHz bandwidth may contain the same content,represented as 2. In an aspect, in 160 MHz transmission, two SIG-Bcoding blocks are transmitted, where each SIG-B coding block spanning 20MHz is replicated four times in frequency domain to result in a SIG-Bfield that span 160 MHz. Each SIG-B coding block contains controlinformation of resources in four 20 MHz blocks.

Each SIG-B coding block contains control information of resources for arespective 20 MHz block. FIGS. 11A, 11B, 11C, and 11D illustrateexamples of such SIG-B mapping for a 20 MHz, a 40 MHz, an 80 MHz, and a160 MHz channel bandwidth, respectively.

Each coding block of the SIG-B field may include a common block fieldand a user specific field. The common block field may include multipleRU allocation fields, where each RU allocation field is associated withresource allocation in a respective 20 MHz bandwidth. For instance, inFIG. 11B, the SIG-B field includes “RU Allocation Signaling Channel A(20 MHz)” and its corresponding “Per-User Allocation Information”, and“RU Allocation Signaling Channel B (20 MHz)” and its corresponding“Per-User Allocation Information”. The RU allocation field denoted as“RU Allocation Signaling Channel A (20 MHz)” may designate a first setof stations and the “Per-User Allocation Information” adjacent to the“RU Allocation Signaling Channel A (20 MHz)” may include user specificinformation for the first set of stations. The RU allocation fielddenoted as “RU Allocation Signaling Channel B (20 MHz)” may designate asecond set of stations and the “Per-User Allocation Information”adjacent to “RU Allocation Signaling Channel B (20 MHz)” may includeuser specific information for the second set of stations. In an aspect,the RU allocation field may be 8 bits per 20 MHz bandwidth. In thisaspect, each of the “RU Allocation Signaling Channel A” and “RUAllocation Signaling Channel B” is associated with a respective 20 MHzband and includes 8 bits.

For 80 MHz transmission, the content of the HE-SIG-B field in the firstand third 20 MHz bands, denoted as A and C, respectively, is identical(indicated by DUP in FIG. 11C). The information carried in either ofthese bands may be referred to as HE-SIG-B channel 1. HE-SIG-B channel 1carries signaling information for all STAs whose payloads occupy sometones in the first or third 20 MHz bands. Similarly, the content of theHE-SIG-B field in the second and fourth 20 MHz bands, denoted as B andD, respectively, are identical. The information carried in either ofthese bands may be referred to as HE-SIG-B channel 2. HE-SIG-B channel 2carries signaling information for all STAs whose payloads occupy sometones in the second or fourth 20 MHz bands. In an aspect, the RUallocation field may be 8 bits per 20 MHz bandwidth. In this aspect,each of the “RU Allocation Signaling #Channel A”, “RU AllocationSignaling #Channel C”, “RU Allocation Signaling #Channel B”, and “RUAllocation Signaling #Channel D” is associated with a respective 20 MHzband and includes 8 bits. In an aspect, the RU allocation field in each20 MHz band may be encoded together. For instance, the “RU AllocationSignaling #Channel A” and “RU Allocation Signaling #Channel C” of thefirst 20 MHz band may be encoded together.

For 160 MHz transmission, the content of the HE-SIG-B field in thefirst, third, fifth, and seventh 20 MHz bands, denoted as A1, C1, A2,and C2, are identical. The information carried in any of these bands maybe referred to as HE-SIG-B channel 1. HE-SIG-B channel 1 carriessignaling information for all stations whose payloads occupy some tonesin the first or third or fifth or seventh 20 MHz band. Similarly, thecontent of the HE-SIG-B field in the second, fourth, sixth, and eighth20 MHz bands, denoted as B1, D1, B2, and D2, are identical. Theinformation carried in any of these bands may be referred to as HE-SIG-Bchannel 2. HE-SIG-B channel 2 carries signaling information for all STAswhose payloads occupy some tones in the second or fourth or sixth oreighth 20 MHz band.

In one or more aspects, methods are provided for identifying a userspecific subfield format. In an aspect, there may be a different amountof STA specific information depending on each STA. For example, STA1assigned for SU-MIMO in RU of OFDMA and STA2 assigned for MU-MIMO in RUof OFDMA may need different subfields to indicate control information ofits own scheme. In order to correctly calculate and find subfieldsdesignated to each STA, a Type subfield that contains a Type indicationmay be introduced in a SIG field (e.g., SIG-B field) for IEEE 802.11ax.In accordance with its Type, a STA specific information of a fixed sizemay be assigned. In other words, the size of the STA specificinformation may be based on the Type. The Type subfield may indicate anSU type (single user allocation), MU type (multi-user allocation),frequency repetition type, and so on in MU. The frequency repetitiontype may indicate to the STA that there are duplicated RUs.

FIG. 12 illustrates an example of an HE-SIG-B field. The HE-SIG-B fieldincludes coding block 1 and coding block 2. Coding block 1 includes acommon block field and STA specific subfields for STA1-1, STA1-2, . . ., STA1-M. Coding block 2 includes a common block field and STA specificsubfields for STA2-1, STA2-2, . . . , STA2-N.

In an aspect, an explicit indication of Type subfield (e.g., SU type, MUtype) may be included within the STA specific control information. Asshown in FIG. 12 , the Type subfield may be located in a front partwithin each STA specific information subfield. In an aspect, the firstbit or first bits of the STA specific information subfield may be theindication. In an aspect, the Type subfield and/or the Type indicationmay be one bit. For instance, this bit may be the first bit of each userspecific field. After the common block field of each content channel,once each station detect/decodes its STA specific subfield correctly,the station determines the type and the size (e.g., expected size) ofits own STA specific information.

FIG. 13 illustrates an example of an HE-SIG-B field. The descriptionfrom FIG. 12 generally applies to FIG. 13 , with examples of differencesbetween FIG. 12 and FIG. 13 and other description provided herein forpurposes of clarity and simplicity. In an aspect, as shown in FIG. 13 ,the HE-SIG-B field may include the Type subfield or the Type informationwithin the common control information (e.g., common block field). Insuch an aspect, the Type subfield or Type information may include anindication of each user's STA specific control information format type(e.g. SU-based format, MU-based format). Each STA may determine theformat type of the STA specific information based on information (e.g.,the indication) included in the common information subfield. By way ofnon-limiting example, the information given in the common informationfield may include allocated RU size for the corresponding STA specificinformation and number of scheduled users for the allocated RU size. Inan aspect, based on an RU allocation and size of each RU indicated bythe Type subfield in the common information, a STA may easily find itsown STA specific information block.

FIG. 14 illustrates an example of an 80 MHz numerology with the special26 RU labeled. The special 26 RU is denoted as 805. The special 26 RUmay be in the middle of the 80 MHz operating bandwidth. In an aspect,the special 26 RU may be assigned to either coding block 1 or codingblock 2. In another aspect, if common information and STA specificinformation of a coding block is assumed to apply to the correspondingsubband channel, the special 26 RU may be assigned to coding block 1 andcoding block 2 since the special 26 RU does not have explicitly thecorresponding subband channel. This may cause the same STA specificinformation subfield associated with the special 26 RU to exist in thetwo coding blocks.

In one or more aspects, resource allocation of the special 26 RU may besignaled in the HE-SIG-B field. Methods are provided for conveyingcontrol information for the special 26 RU in 80 MHz and 160 MHz OFDMAdata transmission. The conveying of such control information mayfacilitate reduction in signaling overhead.

In the case of 80 MHz transmission, 80+80 MHz transmission, or 160 MHztransmission, a transmitter may be able to transmit (e.g., may beallocated) a special RU located in the center of each 80 MHz band. Thespecial RU may have a size of 26 subcarriers. In an aspect, the special26 RU may be referred to as a special central RU, special center 26 RU,special center 26, special center 26 unit, center 26 unit, or variantsthereof. The special 26 RU in the case of 80 MHz signal transmission isshown in FIG. 14 and denoted as 805. The center 26 RU is split into two13 subcarrier blocks due to the 7 DC tones in the center.

With reference back to FIG. 14 , the two transmission subbands of theSIG-B field are denoted as 1 and 2. In an aspect, because the special 26RU exist on the boundary of the transmission subbands of the SIG-Bfield, the special 26 RU may be allowed to be signaled in one or both ofthe SIG-B coding blocks.

In some aspects, control information, such as resource allocation, forthe center 26 RU may be signaled in (e.g., transmitted in) the HE-SIG-Bfield in the primary 20 MHz channel. In an aspect, the primary 20 MHzchannel may be channel 1 or channel 2. The AP may select either channel1 or channel 2 as the primary 20 MHz channel, and may indicate to thestations which channel is the primary 20 MHz channel when the AP engageswith the stations (e.g., during an association procedure between the APand the stations). Depending on the implementation, a station may detectand decode the one coding block over the primary channel and find its RUallocation as the special 26 RU.

In an aspect, when the AP is operating in 80 MHz channel bandwidth, theAP may designate any one of the four 20 MHz blocks within the 80 MHzchannel bandwidth as the primary 20 MHz channel. The AP may signal thedesignated primary 20 MHz channel during an association procedurebetween the AP and the stations. In an aspect, because the primary 20MHz channel is static (e.g., chosen for a long term basis), each stationcan determine the primary 20 MHz channel before the station receives theHE-SIG-B field or portions (e.g., coding blocks) thereof. The commoninformation field of the HE-SIG-B field occupying the primary 20 MHz mayhave additional signaling for the special 26 RU allocation.

In some aspects, the SIG-B field transmission structure can be modifiedsuch that the center special 26 RU is centered within the transmissionsignal bandwidth of a single SIG-B coding block. In an aspect, thespecial 26 RU may be assigned to only one coding block without anyambiguity. FIG. 15 illustrates an example of such a SIG-B codingstructure for a 40 MHz, 80 MHz, and 160 MHz channel bandwidth. With theSIG-B coding structure of FIG. 15 , control information for the special26 RU can be conveyed in a second SIG-B coding block, denoted by thenumber 2 in FIG. 15 . In some aspects, resource allocation of thespecial 26 RU may be signaled with a STA specific subfield (e.g., anadditional/extra STA specific subfield). In an aspect, the RU allocationfield of the common information subfield of the SIG-B field (e.g., ineach HE-SIG-B coding block) may contain resource allocation information(e.g., resource assignments) of all RUs except the special 26 RU. Thepresence of the special 26 RU may be conveyed by transmissions of anextra STA specific subfield in either one of the SIG-B coding blocks.

In an aspect, without additional indication, resource allocation of thespecial 26 RU may be located in either coding block 1 or coding block 2depending on load balance. In accordance with different circumstances,there may exist an unbalanced RU allocation and/or an unbalanced numberof STAs distribution, which may lead to an unbalanced amount of controlinformation in coding block 1 and coding block 2. For instance, codingblock 1 may include information associated with more stations thancoding block 2. In these cases, in order to match the end of an OFDMsymbol for the two coding blocks, padding (e.g., padding bits) mayoccupy the rest of the OFDM symbol. In this regard, it is noted that, ingeneral, coding block 1 and coding block 2 are padded with dummy bits(e.g., a non-valid STA specific information) such that the number ofOFDM symbols for the two SIG-B coding blocks is identical. In an aspect,at least some of the padding may be replaced with control informationfor signaling resource allocation information of the special 26 RU. Inother words, an empty room/space (e.g., generally containing padding) ofeither coding block 1 or coding block 2, or both, may be utilized tocontain STA specific information of the special 26 RU.

FIG. 16 illustrates an example of an HE-SIG-B field including a subfield(e.g., STA specific subfield) associated with the special 26 RU. Thesubfield associated with the special 26 RU is denoted as Center RU26. Inan aspect, the common information subfield of coding block 1 of theSIG-B field may contain information that indicates M number of resourceunit blocks (e.g., M number of STA specific information blocks) followthe common information subfield of coding block 1. These M stations maybe identified as STA-1, STA1-2, . . . STA1-M. Similarly, the commoninformation subfield of coding block 2 may contain information thatindicates N number of resource unit blocks (e.g., N number of STAspecific information blocks) follow the common information subfield ofcoding block 2. These N stations may be identified as STA2-1, STA2-2, .. . STA2-N. In an aspect not shown in FIG. 16 , the M stations of codingblock 1 may be identified as STA1, STA2, . . . STA M, and the N stationsof coding block 2 may be identified as STA1, STA2, . . . , STA N, whereSTA1 of coding block 1 is different from STA1 of coding block 2, STA2 ofcoding block 2 is different from STA2 of coding block 2, and so forth.The values for M and N may be, but need not be, the same.

The common information field in each HE-SIG-B coding block contains theresource assignments other than the special 26 RU. In an aspect, thereexists an implicit (or explicit) mapping between the RU assigned and theorder and the number the STA specific information (denoted as STA1-1,STA1-2, . . . , STA-M field in FIG. 16 ). In an aspect, the receiver maybe able to identify the total number of STA specific information (e.g.,M value) from parsing the common information field. If the total lengthof the HE-SIG-B coding block is long enough such that special RU 26control information can be inserted between the last STA specificinformation and the end of the HE-SIG B coding block, then the receivercan assume that there is a special RU 26 assigned and can parse thatinformation field (e.g., for assignment check).

In an aspect, if there exists a STA specific subfield (e.g., a valid STAspecific subfield) after either the M STA specific information blocks ofcoding block 1 and/or after the N STA specific information blocks ofcoding block 2, then the STA may assume that it is for the special 26RU. The validity of the STA specific subfield for the special 26 RU canbe checked using, for instance, a cyclic redundancy check (CRC) andSTA-ID. In an aspect, in order to distinguish between the special RU 26assignment and bit padding for the HE-SIG-B coding block, the special RU26 may include a specific bit (e.g., one bit) or a specific bit sequence(e.g., including multiple bits) that is different from a padding bitsequence such that the receiver is able to differentiate between thespecial RU 26 assignment and padding bits.

As shown in FIG. 16 , when there is empty room/space within coding block1, the STA specific information of the special 26 RU may be allowed tobe included in coding block 1. In an aspect, no common informationindicates the presence of RU allocation of the special 26 RU. In anaspect, since the stations can distinguish between padding bits and STAspecific information, such as MCS, AID, etc., the stations are able toidentify the subfield associated with the special 26 RU.

In some aspects, if the special 26 RU is assigned, the user specificfield for the special 26 RU in a channel bandwidth greater than or equalto 80 MHz (e.g., 80 MHz, 80+80 MHz, 160 MHz) may be located at the endof user specific fields in either SIG-B content channel 1 or SIG-Bcontent channel 2. In some cases, such as shown in FIG. 16 , the userspecific field of the special 26 RU may be in SIG-B content channel 1.For instance, for 80 MHz, the user specific field for the special 26 RUmay be included in SIG-B content channel 1. In other cases, the userspecific field of the special 26 RU may be in SIG-B content channel 2.In an aspect, the user specific field may be in SIG-B content channel 1for a lower 80 MHz band and SIG-B content channel 2 for an upper 80 MHzband in the 160 MHz channel bandwidth. An HE-SIG-B field with thespecial 26 RU is described, for example, with respect to FIGS. 16, 17,19A, and 19B.

FIG. 17 illustrates another example of an HE-SIG-B field including asubfield (e.g., STA specific subfield) associated with the special 26RU. The description from FIG. 16 generally applies to FIG. 17 . In FIG.17 , the STA specific information subfield associated with the specialcenter 26 RU is denoted as Special RU26 control information.

In some aspects, the SIG-B field may be separately encoded on each 20MHz band. In an aspect, the SIG-B field is encoded on a per 20 MHz basisusing BCC with common and user blocks separated in the bit domain. TheSIG-B field can be composed of multiple BCC blocks. The encoding of theSIG-B field in multiple BCC blocks may assist/facilitate decoding.

FIG. 18 illustrates an example of an HE-SIG-B field encoded as BCCblocks. Each BCC block may include information bits (e.g., commoninformation, STA specific information) and tail bits (e.g., 6 tail bits)for trellis termination. In FIG. 18 , the common information subfield isencoded in a single BCC block, and every two STA specific informationsubfield are encoded in a single BCC block. In other words, two users(e.g., two STAs) are grouped together and jointly encoded in each BCCblock in the user specific field of the SIG-B field. In a case thatthere are an odd number of STA specific information subfields, the lastSTA specific information subfield (one STA specific informationsubfield) can be encoded in a single BCC block. In an aspect, the commonblock has a CRC separate from a CRC of the user specific blocks.

In some aspects, additional signaling may be conveyed in the SIG-B field(or in the SIG-A field) to indicate the extra presence of STA specificinformation subfield(s) other than those indicated by resourceallocation field of the common information subfield. In this regard, theadditional signaling may indicate the presence of a STA specificinformation subfield associated with the special center 26 RU. Forinstance, the STA specific information subfield associated with thespecial center 26 RU is denoted as Center RU26 in FIG. 16 and SpecialRU26 control information in FIG. 17 . In an aspect, the BCC block isdefined for every two consecutive STA specific information subfields,including the STA specific information subfield for the special 26 RU.

In an aspect, the RU allocation subfield of the common informationsubfield of the SIG-B field (e.g., in each HE-SIG-B coding block) maycontain resource allocation information (e.g., resource assignments) ofall RUs except the special 26 RU. In an aspect, the additional signalingmay be an indication or an indication signal whose value is indicativeof whether the special 26 RU is allocated and, thus, whether an extrapresence of STA specific information subfield(s) associated with theallocation of the special 26 RU is contained in the SIG-B field. Forinstance, when the indication is set to a first value (e.g., 1), thespecial 26 RU is allocated. When the indication is set to a second value(e.g., 0), the special 26 RU is not allocated. In an aspect, such anindication may be contained in a center 26-tone RU subfield of thecommon information subfield of the SIG-B field.

In one or more aspects, the common information subfield may include theRU allocation subfield, the center 26-tone RU subfield, a cyclicredundancy check (CRC) subfield, and a tail subfield. In an aspect, theadditional signaling for the special 26 RU may be between the RUallocation information (e.g., contained in the RU allocation subfield)in the common information subfield and station specific information. Inan aspect, the additional signaling may be immediately after the RUallocation information. In an aspect, the additional signaling may be inboth coding block 1 and 2. In an aspect, the additional signaling mayinclude one bit. In an aspect, for an 80 MHz channel bandwidth, theadditional signaling (e.g., 1 bit) may be included in both coding block1 and 2 to indicate if the special 26 RU is allocated. In an aspect, fora full bandwidth of 80 MHz, add 1 bit to indicate if center 26-tone RUis allocated in the common block fields of both SIG-B content channelswith same value. In other words, for an 80 MHz channel bandwidth, add 1bit with the same value in the common block fields of both SIG-B contentchannels if the center 26-tone RU is allocated.

In an aspect, for a 160 MHz or 80+80 MHz channel bandwidth, theadditional signaling (e.g., 1 bit) may be included in both coding block1 and 2 to indicate if the special 26 RU of one of the 80 MHz bands isallocated. In an aspect, for a full bandwidth of 160 MHz or 80+80 MHz,add 1 bit to indicate if center 26-tone RU is allocated for oneindividual 80 MHz in the common block fields of both SIG-B contentchannels. In other words, for a 160 MHz or 80+80 MHz channel bandwidth,add 1 bit in the common block fields of both SIG-B content channels toindicate if the center 26-tone RU for one individual 80 MHz isallocated.

FIG. 19A illustrates an example of an HE-SIG-B field. The BCC block isdefined for every two consecutive STA specific information subfields(including the STA specific information subfield for the special 26 RU).In FIG. 19A, a BCC block 1905 includes STA specific information for STAM as well as for the special 26 RU. In this regard, the special 26 RU isincluded at an end of the STA specific information. Additional signalingmay also be conveyed in the SIG-B field (or in the SIG-A field) toindicate the extra presence of STA specific information subfield(s)other than those indicated by the RU allocation information in thecommon information subfield. In this regard, the additional signalingmay indicate the presence of a STA specific information subfieldassociated with the special center 26 RU. In some cases, M may be oddand N may be even. For instance, in a case that the number of STAspecific information subfield of FIG. 19A indicated by the commoninformation subfield is odd, and one or more of the special 26 RU STAspecific information exist, the STA specific information for the special26 RU may be paired with STA specific information for other RUs withinthe BCC block 1905.

FIG. 19B illustrates an example of the HE-SIG-B field of FIG. 19A withan indication 1910 of the special center 26 RU explicitly depicted. Theindication 1910 of the special center 26 RU is denoted as RU26 IND. Inan aspect, the indication 1910 may be 1 bit. The indication 1910 may bebetween the RU allocation information in the common information subfield1915 (e.g., a BCC block in which the common information subfield 1915 isencoded) and a first BCC block 1920 associated with station specificinformation. In an aspect, CRC bits and tail bits may follow theindication 1910 in the common information subfield 1915.

In some aspects, the STA specific information subfield for the special26 RU may be defined as a separate BCC block. In an aspect, in a casewhen the number of STA specific information subfields indicated by thecommon information subfield is odd and the total number is M, only oneSTA specific information subfield exists for the BCC block that containsthe M^(th) STA specific information subfield. The STA specificinformation subfield(s) for the special 26 RU may form a new BCC blockfollowing the M^(th) STA specific information subfield.

In some aspects, the STA specific information subfield(s) for thespecial 26 RU may be mapped on a different SIG-B OFDM symbol from therest of the STA specific information subfield(s). In contrast, in somecases, the STA specific information subfield for the special 26 RU maybe logically appended to the rest of the STA specific informationsubfield(s) and is not necessarily separated in different OFDM symbols.In this regard, FIG. 20 illustrates an example of an HE-SIG-B field inwhich the special 26 RU may be, but need not be, mapped to a differentOFDM symbol. For instance, in FIG. 20 , the special 26 RU subfield mayfit in the SIG-B field without an added OFDM symbol if there issufficient space after the STA2-N specific information subfield.

FIG. 21 illustrates an example of an HE-SIG-B field in which the special26 RU is mapped to a different OFDM symbol. In such a case, after theSTA specific information for RUs other than the special 26 RU, dummyinformation may be included as padding such that the common subfield,STA specific information subfield, and padding (e.g., padding bit(s))fill an integer number of OFDM symbols. As shown in FIG. 21 , the STAspecific information subfield for the special 26 RU, denoted as CenterRU26, is mapped to the next OFDM symbol (e.g., following a last STAspecific information subfield in both coding block 1 and coding block2). For coding block 1, padding may be present in the gap between STA1-Mand Center RU26. For coding block 2, padding may be present in the gapbetween STA2-N and Center RU26. In an aspect, because the STA specificinformation subfield for the special 26 RU is transmitted in a separateOFDM symbol (e.g., in FIG. 21 ), it is possible to change the MCS forthe OFDM symbol containing the STA specific information subfield for thespecial 26 RU.

In an aspect, compressed OFDM symbol duration can be applied to the OFDMsymbols containing the STA specific information subfield for the special26 RU. In an aspect, a compressed OFDM symbol duration may be denoted as2× whereas a non-compressed OFDM symbol duration may be denoted as 4×.FIG. 22 illustrates an example of an HE-SIG-B field in which the special26 RU is mapped to a compressed OFDM symbol. The description from FIG.21 generally applies to FIG. 22 , with examples of differences betweenFIG. 21 and FIG. 22 and other description provided herein for purposesof clarity and simplicity. The compressed OFDM symbol may potentiallyhave a smaller DFT duration compared with other (e.g., non-compressed)SIG-B OFDM symbols. The compressed OFDM symbol shown in FIG. 22 may behalf the size (e.g., half the number of bits) of the OFDM symbol of FIG.21 .

In one or more implementations, methods are provided for facilitatingrepetition in the frequency domain. In an aspect, the repetition may bereferred to as a duplication. In some aspects, RU repetition in terms ofthe frequency domain may be utilized because soft combining of thereceived RUs may facilitate extension of communication range andimproved performance (e.g., such as for outdoors). In some cases,without payload available for outdoor circumstances, the large range ofL-SIG/HE-SIG-A in the preamble may be meaningless. In an aspect, the RUrepetition may be referred to as RU duplication. In an aspect, aduplicated mode in OFDMA may be applied to any RU(s).

In an aspect, a non-continuous RU that includes two duplicated half-toneRUs may be assigned for (e.g., allocated to) a STA in OFDMA. In a casewith limited supported interleaver and tone mapper size, a WLAN devicemay or may not be able to decode the non-continuous RU (e.g., dependingon the size of the non-continuous RU). For example, if the interleaverand tone mapper are designed for only the same number of tones to RUs,assigning the non-continuous RU for the station may only allow forassigning of a non-continuous 52-tone RU that includes two 26-tone RUsas shown in FIG. 23 . In an aspect, any two non-continuous 26-tone RUscould be paired with identical content (e.g., HE-DATA) in any operatingbandwidth channels. For instance, in FIG. 23 , the two 26-tone RUs withgray shading may be paired. In an aspect, the duplication of the samecontent in multiple RUs may facilitate decoding of the content by thereceiver.

In an aspect, a continuous or non-continuous RU including two (or more)duplicated RUs may be assigned for STAs using RUs in OFDMA numerology.In this regard, any size of RU may be allowed. For example, FIG. 24illustrates an example in which two identical 52-tone RUs (shaded ingray) are paired.

In an aspect, the RU repetition may be applied to a trigger frame,including a trigger frame that allocates RU for random access, whenrobust coverage for communication links is desired. A trigger frame thatallocates RU for random access may be referred to as trigger frame-R. Itis noted that the trigger frame sent by the AP is utilized to indicatethat UL MU PPDUs are to be sent as an immediate response to triggerframe.

In a case where the trigger frame may be in a PPDU that is to betransmitted to multiple (and/or random) STAs, securing enough coveragemay be helpful. FIG. 25A illustrates an example in which anon-continuous RU that includes two duplicated half-tone RUs (such asshown in FIG. 23 ) may be assigned for (e.g., allocated to) a STA inOFDMA. FIG. 25B illustrates an example in which a non-continuous RU thatincludes two duplicated RUs (such as shown in FIG. 24 ) may be assignedfor (e.g., allocated to) a STA in OFDMA.

In an aspect, the RU repetition may be applied to a beacon frame, whichmay be duplicated on every 20 MHz or through part of an operatingchannel bandwidth. A beacon bit indicating duplicated mode may be in theHE information element.

Repeated RUs position could be indicated one by one, which may increasesignaling overhead. For multi-user OFDMA transmission, the signaling ofthe multi-RU signal transmission (described above) can be conveyedeither in the common information or user specific information of SIG-B.

In one or more aspects, options are provided for including controlinformation indication associated with repeated RUs.

Option A) Duplicated RUs paired with even (or odd) indices within anentire/part of an operating bandwidth or assigned resource for randomaccess.

Option B) A first RU position in terms of frequency index and one moresubfield indicating equal distance between paired RUs. They are withinan entire/part of an operating bandwidth or assigned resource for randomaccess.

In an aspect, since the transmission that utilizes repetition infrequency can be used to improve reception reliability of signals, suchtransmission may be utilized in the extended range PPDU format, anexample of which is shown in FIG. 7 . In an aspect, the transmissionwould still utilize the RUs defined for the OFDMA numerology, examplesof which are shown in FIGS. 8A, 8B, and 8C.

For example, two 106 RUs may be used in extended range PPDU format. Thetwo 106 RUs can carry identical data information. FIG. 26 illustrates anexample of a transmitted PPDU signal structure. The x-axis (horizontal)represents the time domain and the y-axis (vertical) represents thefrequency domain. The lower frequency 106 RU is a duplicate of (e.g.,contains the same data as) the upper frequency 106 RU.

FIG. 27 illustrates an example of a frequency domain representation of adata field (e.g., HE-DATA field) portion of a PPDU for the example ofrepeated 106 RU transmission in 20 MHz PPDU. In an aspect, the two 106RUs are from the OFDMA numerology for the 20 MHz transmission. The emptytones in FIG. 26 may include the 26 tones and 7 DC tones between the two106 RUs, which are not used for the extended range PPDU. In an aspect,in FIG. 26 , since the 20 MHz numerology includes only two 106 tones,the repeating of the information content in the two 106 tones need notbe indicated. In an aspect, when the extended range PPDU is transmitted,the extended range PPDU is being transmitted such that the content inthe two 106 tones are identical.

FIG. 28 illustrates an example of a frequency domain representation of adata field (e.g., HE-DATA field) portion of a PPDU for the example ofrepeated 52 RU transmission in 20 MHz PPDU. In FIG. 28 , four 52 RUs areused for repeated signal transmission. Each of the 52 RU containsidentical data information content. The duplicated information (e.g.,HE-DATA field) is sent in each of the four 52 RU positioning using theOFDMA numerology for 20 MHz.

FIGS. 29 and 30 illustrate examples of a frequency domain representationof a data field (e.g., HE-DATA field) portion of a PPDU for the exampleof repeated 52 RU transmission in 20 MHz PPDU. Two 52 RU are used forrepeated signal transmission. Each of the 52 RU contains identical datainformation content. The duplicated information is sent in each of thetwo 52 RU positioning using the OFDMA numerology for 20 MHz. Thedifference between the examples in FIGS. 29 and 30 are whether signalsare transmitted in the inner two 52 RUs or outer 52 RUs of the 20 MHzchannel bandwidth. In an aspect, using the inner two 52 RUs may have thebenefit of having less interference from adjacent 20 MHz channels.

In one aspect, information that is identically duplicated in thefrequency domain may cause higher peak to average power ratio (PAPR).Signals resulting in higher PAPR may likely be transmitted using a lowertransmit power, such that signal clipping and non-linear signaldistortion does not occur. In an aspect, in order to avoid high PAPR, itmay be possible to scramble (e.g., multiply) the duplicated signals witha different scramble sequence.

For example, in FIG. 27 , the lower frequency 106 RU is regularly sent(e.g., without modification), while the upper frequency 106 RU may bescrambled with a scrambling sequence in each OFDM symbol. Even if thetwo 106 RU contain the same content (e.g., content isrepeated/duplicated), the scrambling of the upper 106 RU may mitigate(e.g., reduce) high PAPR of the transmission signal.

In another aspect, to reduce high PAPR, symmetric mapping of signals maybe utilized. FIG. 31 illustrates an example of a symmetric mapping ofsignals. The repeated signals can be mirror symmetric (or conjugatemirror symmetric) mapping of data modulated tones (e.g., binaryphase-shift keying (BPSK) or quadrature phase-shift keying (QPSK)modulated symbols) with respect to a center DC tone. In some cases, acombination of mirror symmetric signals and scrambling may be utilizedto reduce high PAPR.

In an aspect, in case of dual carrier modulated (DCM) signals,information content can be duplicated even within a RU (either 106-,52-, or 26-RU). The repetition for robust transmission may be applied ontop of the DCM. This may effectively result in four times repeatedsignals for two 106 RU (or two 52 RU) transmission.

It should be noted that like reference numerals may designate likeelements. These components with the same reference numerals have certaincharacteristics that are the same, but as different figures illustratedifferent examples, the same reference numeral does not indicate that acomponent with the same reference numeral has the exact samecharacteristics. While the same reference numerals are used for certaincomponents, examples of differences with respect to a component aredescribed throughout this disclosure.

The embodiments provided herein have been described with reference to awireless LAN system; however, it should be understood that thesesolutions are also applicable to other network environments, such ascellular telecommunication networks, wired networks, etc.

An embodiment of the present disclosure may be an article of manufacturein which a non-transitory machine-readable medium (such asmicroelectronic memory) has stored thereon instructions which programone or more data processing components (generically referred to here asa “processor” or “processing unit”) to perform the operations describedherein. In other embodiments, some of these operations may be performedby specific hardware components that contain hardwired logic (e.g.,dedicated digital filter blocks and state machines). Those operationsmay alternatively be performed by any combination of programmed dataprocessing components and fixed hardwired circuit components.

In some cases, an embodiment of the present disclosure may be anapparatus (e.g., an AP STA, a non-AP STA, or another network orcomputing device) that includes one or more hardware and software logicstructure for performing one or more of the operations described herein.For example, as described above, the apparatus may include a memoryunit, which stores instructions that may be executed by a hardwareprocessor installed in the apparatus. The apparatus may also include oneor more other hardware or software elements, including a networkinterface, a display device, etc.

FIGS. 32A, 32B, and 32C illustrate flow charts of examples of methodsfor facilitating wireless communication. For explanatory andillustration purposes, the example processes 3210, 3220, and 3230 may beperformed by the wireless communication devices 111-115 of FIG. 1 andtheir components such as a baseband processor 210, a MAC processor 211,a MAC software processing unit 212, a MAC hardware processing unit 213,a PHY processor 215, a transmitting signal processing unit 280 and/or areceiving signal processing unit 290; however, the example processes3210, 3220, and 3230 are not limited to the wireless communicationdevices 111-115 of FIG. 1 or their components, and the example processes3210, 3220, 3230 may be performed by some of the devices shown in FIG. 1, or other devices or components. Further for explanatory andillustration purposes, the blocks of the example processes 3210, 3220,3230 are described herein as occurring in serial or linearly. However,multiple blocks of the example processes 3210, 3220, 3230 may occur inparallel. In addition, the blocks of the example processes 3210, 3220,3230 need not be performed in the order shown and/or one or more of theblocks/actions of the example processes 3210, 3220, 3230 need not beperformed.

Various examples of aspects of the disclosure are described below asclauses for convenience. These are provided as examples, and do notlimit the subject technology. As an example, some of the clausesdescribed below are illustrated in FIGS. 32A, 32B, and 32C.

Clause A. An access point for facilitating communication in a wirelessnetwork for a multi-user transmission, the access point comprising: oneor more memories; and one or more processors coupled to the one or morememories, the one or more processors configured to cause: generating afirst frame for allocating resources to a plurality of stations, whereinthe first frame contains an indication as to whether at least one of aset of resource units of a plurality of resource units is allocated toat least one station of the plurality of stations; and transmitting thefirst frame to the plurality of stations for the multi-usertransmission, wherein the multi-user transmission is associated with afirst channel bandwidth or a second channel bandwidth, wherein a size ofthe second channel bandwidth is different from a size of the firstchannel bandwidth, and wherein the at least one of the set of resourceunits consists of a resource unit, two of a plurality of tones of theresource unit being separated by a plurality of direct current (DC)tones.

Clause B. A computer-implemented method of facilitating communication ina wireless network for a multi-user transmission, thecomputer-implemented method comprising: receiving, at a first station, afirst frame from a second station for allocating resources to aplurality of stations; determining, based on an indication contained inthe first frame, whether at least one of a set of resource units of aplurality of resource units is allocated to the first station, whereinat least one of a first HE-SIG-B field of the first frame or a secondHE-SIG-B field of the first frame comprises a station specific subfieldassociated with the at least one of the set of resource units of theplurality of resource units when the at least one of the set of resourceunits is allocated; and transmitting, for the multi-user transmission, asecond frame using the at least one of the set of resource units to theplurality of stations when the at least one of the set of resource unitsis allocated to the first station, wherein: the first HE-SIG-B field isassociated with a first portion of a channel bandwidth, and the secondHE-SIG-B field is associated with a second portion of the channelbandwidth, the channel bandwidth is associated with a first bandwidthsize or a second bandwidth size, wherein the second bandwidth size isdifferent from the first bandwidth size, and the at least one of the setof resource units consists of a resource unit, two of a plurality oftones of the resource unit being separated by a plurality of directcurrent (DC) tones.

Clause C. A station for facilitating communication in a wireless networkfor a multi-user transmission, the station comprising: one or morememories; and one or more processors coupled to the one or morememories, the one or more processors configured to cause: receiving afirst frame for allocating resources to a plurality of stations;determining, based on an indication contained in the first frame,whether at least one of a set of resource units of a plurality ofresource units is allocated to the station; and transmitting, for themulti-user transmission, a second frame using one or more of theplurality of resource units based on the first frame, wherein themulti-user transmission is associated with a first channel bandwidth ora second channel bandwidth, wherein a size of the second channelbandwidth is different from a size of the first channel bandwidth, andwherein the at least one of the set of resource units consists of aresource unit, two of a plurality of tones of the resource unit beingseparated by a plurality of direct current (DC) tones.

In one or more aspects, additional clauses are described below.

A method comprising one or more methods or operations described herein.

An apparatus or a station comprising one or more memories (e.g., 240,one or more internal, external or remote memories, or one or moreregisters) and one or more processors (e.g., 210) coupled to the one ormore memories, the one or more processors configured to cause theapparatus to perform one or more methods or operations described herein.

An apparatus or a station comprising one or more memories (e.g., 240,one or more internal, external or remote memories, or one or moreregisters) and one or more processors (e.g., 210 or one or moreportions), wherein the one or more memories store instructions that,when executed by the one or more processors, cause the one or moreprocessors to perform one or more methods or operations describedherein.

An apparatus or a station comprising means (e.g., 210) adapted forperforming one or more methods or operations described herein.

A computer-readable storage medium (e.g., 240, one or more internal,external or remote memories, or one or more registers) comprisinginstructions stored therein, the instructions comprising code forperforming one or more methods or operations described herein.

A computer-readable storage medium (e.g., 240, one or more internal,external or remote memories, or one or more registers) storinginstructions that, when executed by one or more processors (e.g., 210 orone or more portions), cause the one or more processors to perform oneor more methods or operations described herein.

In one aspect, a method may be an operation, an instruction, or afunction and vice versa. In one aspect, a clause may be amended toinclude some or all of the words (e.g., instructions, operations,functions, or components) recited in other one or more clauses, one ormore sentences, one or more phrases, one or more paragraphs, and/or oneor more claims.

To illustrate the interchangeability of hardware and software, itemssuch as the various illustrative blocks, modules, components, methods,operations, instructions, and algorithms have been described generallyin terms of their functionality. Whether such functionality isimplemented as hardware or software depends upon the particularapplication and design constraints imposed on the overall system.Skilled artisans may implement the described functionality in varyingways for each particular application.

A reference to an element in the singular is not intended to mean oneand only one unless specifically so stated, but rather one or more. Forexample, “a” module may refer to one or more modules. An elementproceeded by “a,” “an,” “the,” or “said” does not, without furtherconstraints, preclude the existence of additional same elements.

Headings and subheadings, if any, are used for convenience only and donot limit the invention. The word exemplary is used to mean serving asan example or illustration. To the extent that the term include, have,or the like is used, such term is intended to be inclusive in a mannersimilar to the term comprise as comprise is interpreted when employed asa transitional word in a claim. Relational terms such as first andsecond and the like may be used to distinguish one entity or action fromanother without necessarily requiring or implying any actual suchrelationship or order between such entities or actions.

Phrases such as an aspect, the aspect, another aspect, some aspects, oneor more aspects, an implementation, the implementation, anotherimplementation, some implementations, one or more implementations, anembodiment, the embodiment, another embodiment, some embodiments, one ormore embodiments, a configuration, the configuration, anotherconfiguration, some configurations, one or more configurations, thesubject technology, the disclosure, the present disclosure, othervariations thereof and alike are for convenience and do not imply that adisclosure relating to such phrase(s) is essential to the subjecttechnology or that such disclosure applies to all configurations of thesubject technology. A disclosure relating to such phrase(s) may apply toall configurations, or one or more configurations. A disclosure relatingto such phrase(s) may provide one or more examples. A phrase such as anaspect or some aspects may refer to one or more aspects and vice versa,and this applies similarly to other foregoing phrases.

A phrase “at least one of” preceding a series of items, with the terms“and” or “or” to separate any of the items, modifies the list as awhole, rather than each member of the list. The phrase “at least one of”does not require selection of at least one item; rather, the phraseallows a meaning that includes at least one of any one of the items,and/or at least one of any combination of the items, and/or at least oneof each of the items. By way of example, each of the phrases “at leastone of A, B, and C” or “at least one of A, B, or C” refers to only A,only B, or only C; any combination of A, B, and C; and/or at least oneof each of A, B, and C.

It is understood that the specific order or hierarchy of steps,operations, or processes disclosed is an illustration of exemplaryapproaches. Unless explicitly stated otherwise, it is understood thatthe specific order or hierarchy of steps, operations, or processes maybe performed in different order. Some of the steps, operations, orprocesses may be performed simultaneously. The accompanying methodclaims, if any, present elements of the various steps, operations orprocesses in a sample order, and are not meant to be limited to thespecific order or hierarchy presented. These may be performed in serial,linearly, in parallel or in different order. It should be understoodthat the described instructions, operations, and systems can generallybe integrated together in a single software/hardware product or packagedinto multiple software/hardware products.

The disclosure is provided to enable any person skilled in the art topractice the various aspects described herein. In some instances,well-known structures and components are shown in block diagram form inorder to avoid obscuring the concepts of the subject technology. Thedisclosure provides various examples of the subject technology, and thesubject technology is not limited to these examples. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the principles described herein may be applied to otheraspects.

All structural and functional equivalents to the elements of the variousaspects described throughout the disclosure that are known or later cometo be known to those of ordinary skill in the art are expresslyincorporated herein by reference and are intended to be encompassed bythe claims. Moreover, nothing disclosed herein is intended to bededicated to the public regardless of whether such disclosure isexplicitly recited in the claims. No claim element is to be construedunder the provisions of 35 U.S.C. § 112, sixth paragraph, unless theelement is expressly recited using a phrase means for or, in the case ofa method claim, the element is recited using the phrase step for.

The title, background, brief description of the drawings, abstract, anddrawings are hereby incorporated into the disclosure and are provided asillustrative examples of the disclosure, not as restrictivedescriptions. It is submitted with the understanding that they will notbe used to limit the scope or meaning of the claims. In addition, in thedetailed description, it can be seen that the description providesillustrative examples and the various features are grouped together invarious implementations for the purpose of streamlining the disclosure.The method of disclosure is not to be interpreted as reflecting anintention that the claimed subject matter requires more features thanare expressly recited in each claim. Rather, as the following claimsreflect, inventive subject matter lies in less than all features of asingle disclosed configuration or operation. The following claims arehereby incorporated into the detailed description, with each claimstanding on its own as a separately claimed subject matter.

The claims are not intended to be limited to the aspects describedherein, but are to be accorded the full scope consistent with thelanguage claims and to encompass all legal equivalents. Notwithstanding,none of the claims are intended to embrace subject matter that fails tosatisfy the requirements of the applicable patent law, nor should theybe interpreted in such a way.

What is claimed is:
 1. An access point for facilitating communication ina wireless network for a transmission, the access point comprising: oneor more memories; and one or more processors coupled to the one or morememories, the one or more processors configured to cause: generating aframe for transmission to a set of stations, wherein each station in theset of stations is allocated a resource unit from a channel bandwidth ofthe frame, wherein the frame comprises a high efficiency signal-B(HE-SIG-B) field arranged in a plurality of content channels occupyingrespective subbands of the channel bandwidth of the frame, wherein afirst content channel of the plurality of content channels of theHE-SIG-B field contains (1) a first common information field thatincludes (A) resource unit allocation information to allocate a firstset of resource units of the channel bandwidth to a first set of one ormore stations in the set of stations and (B) when the channel bandwidthof the frame satisfies a predetermined bandwidth size, a firstindication as to whether a second set of resource units are allocated toa station in the set of stations and (2) a first set of station specificinformation fields that include station specific information for thefirst set of one or more stations, wherein a second content channel ofthe plurality of content channels of the HE-SIG-B field contains (1) asecond common information field that includes (A) resource unitallocation information to allocate a third set of resource units of thechannel bandwidth to a second set of one or more stations in the set ofstations and (B) when the channel bandwidth of the frame satisfies thepredetermined bandwidth size, a second indication as to whether thesecond set of resource units are allocated to a station in the set ofstations, wherein the first indication has a same value as the secondindication, and (2) a second set of station specific information fieldsthat include station specific information for the second set of one ormore stations, and wherein station specific information associated withthe second set of resource units is located between a last stationspecific information field of the first set of station specificinformation fields and the end of the first content channel of theHE-SIG-B field, and transmitting the frame to the plurality of stationsfor the transmission, including the first content channel and the secondcontent channel of the HE-SIG-B field.
 2. The access point of claim 1,wherein the second set of resource units includes a resource unit thatincludes a first set of tones and a second set of tones, and wherein anumber of tones in the first set of tones is identical to a number oftones in the second set of tones.
 3. The access point of claim 2,wherein the resource unit in the second set of resource units is at acenter of the channel bandwidth of the frame.
 4. The access point ofclaim 2, wherein the first set of tones includes thirteen tones and thesecond set of tones includes thirteen tones such that the second set ofresource units includes twenty-six tones.
 5. The access point of claim2, wherein the first set of tone is separated from the second set oftones by a set of seven direct current tones.
 6. The access point ofclaim 1, wherein the predetermined bandwidth size is 80 MHz such thatone or more of the first indication is present in the first contentchannel of the HE-SIG-B field or the second indication is present in thesecond content channel of the HE-SIG-B field when the channel bandwidthof the frame is 80 MHz or greater, including when the channel bandwidthof the frame is 80+80 MHz.
 7. The access point of claim 6, wherein thechannel bandwidth includes two copies of the first content channel ofthe HE-SIG-B field and two copies of the second content channel of theHE-SIG-B field when the channel bandwidth is 80 MHz.
 8. The access pointof claim 1, wherein the first content channel of the HE-SIG-B field andthe second content channel of the HE-SIG-B field are each duplicated inthe channel bandwidth such that one or more of the first indication andthe second indication is duplicated in the channel bandwidth.
 9. Theaccess point of claim 1, wherein the first common information fieldindicates the number of stations from the set of stations allocated tothe first set of resource units and the second common information fieldindicates the number of stations from the set of stations allocated tothe second set of resource units.
 10. The access point of claim 1,wherein the resource unit allocation information that allocates thefirst set of resource units of the channel bandwidth to the first set ofone or more stations in the set of stations includes resource allocationinformation for the second set of resource units when the firstindication indicates that the second set of resource units are allocatedto the station in the set of stations.
 11. A station for facilitatingcommunication in a wireless network for a transmission, the stationcomprising: one or more memories; and one or more processors coupled tothe one or more memories, the one or more processors configured tocause: receiving a downlink frame for allocating resources to a set ofstations, wherein each station in the set of stations is allocated aresource unit from a channel bandwidth of the downlink frame, whereinthe downlink frame comprises a high efficiency signal-B (HE-SIG-B) fieldarranged in a plurality of content channels occupying respectivesubbands of the channel bandwidth of the downlink frame, wherein a firstcontent channel of the plurality of content channels of the HE-SIG-Bfield contains (1) a first common information field that includes (A)resource unit allocation information to allocate a first set of resourceunits of the channel bandwidth to a first set of one or more stations inthe set of stations and (B) when the channel bandwidth of the downlinkframe satisfies a predetermined bandwidth size, a first indication as towhether a second set of resource units are allocated to a station in theset of stations and (2) a first set of station specific informationfields that include station specific information for the first set ofone or more stations, wherein a second content channel of the pluralityof content channels of the HE-SIG-B field contains (1) a second commoninformation field that includes (A) resource unit allocation informationto allocate a third set of resource units of the channel bandwidth to asecond set of one or more stations in the set of stations and (B) whenthe channel bandwidth of the downlink frame satisfies the predeterminedbandwidth size, a second indication as to whether the second set ofresource units are allocated to a station in the set of stations,wherein the first indication has a same value as the second indication,and (2) a second set of station specific information fields that includestation specific information for the second set of one or more stations,and wherein station specific information associated with the second setof resource units is located between a last station specific informationfield of the first set of station specific information fields and theend of the first content channel of the HE-SIG-B field, processing oneor more of the first common information field, the second commoninformation field, the first set of station specific information fields,and the second set of station specific information fields to determineresource unit assignment for the station in the downlink frame.
 12. Thestation of claim 11, wherein the second set of resource units includes aresource unit that includes a first set of tones and a second set oftones, and wherein a number of tones in the first set of tones isidentical to a number of tones in the second set of tones.
 13. Thestation of claim 12, wherein the resource unit in the second set ofresource units is at a center of the channel bandwidth of the frame. 14.The station of claim 12, wherein the first set of tones includesthirteen tones and the second set of tones includes thirteen tones suchthat the second set of resource units includes twenty-six tones.
 15. Thestation of claim 12, wherein the first set of tones is separated fromthe second set of tones by a set of seven direct current tones.
 16. Thestation of claim 11, wherein the predetermined bandwidth size is 80 MHzsuch that one or more of the first indication is present in the firstcontent channel of the HE-SIG-B field or the second indication ispresent in the second content channel of the HE-SIG-B field when thechannel bandwidth of the frame is 80 MHz or greater, including when thechannel bandwidth of the frame is 80+80 MHz.
 17. The station of claim16, wherein the channel bandwidth includes two copies of the firstcontent channel of the HE-SIG-B field and two copies of the secondcontent channel of the HE-SIG-B field when the channel bandwidth is 80MHz.
 18. The station of claim 11, wherein the first content channel ofthe HE-SIG-B field and the second content channel of the HE-SIG-B fieldare each duplicated in the channel bandwidth such that one or more ofthe first indication and the second indication is duplicated in thechannel bandwidth.
 19. The station of claim 11, wherein the first commoninformation field indicates the number of stations from the set ofstations allocated to the first set of resource units and the secondcommon information field indicates the number of stations from the setof stations allocated to the second set of resource units.
 20. Thestation of claim 11, wherein the resource unit allocation informationthat allocates the first set of resource units of the channel bandwidthto the first set of one or more stations in the set of stations includesresource allocation information for the second set of resource unitswhen the first indication indicates that the second set of resourceunits are allocated to the station in the set of stations.